Bradford's deal is expected to be one year for $20 million, including $15 million guaranteed, with a one-year option for $20 million, according to the source.

The Minnesota Vikings acquired Bradford in a trade with the Philadelphia Eagles after Teddy Bridgewater suffered a knee injury ahead of the 2016 season. The veteran quarterback posted the league's highest completion percentage in his first season with the Vikings, and Bradford, 30, looked poised for a breakout year in 2017.

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Which quarterback will the Cardinals be getting when Bradford signs a one-year contract worth $20 million with $15 million guaranteed?

Things didn't go according to plan. While lighting up the New Orleans Saints in the season opener, Bradford sustained a noncontact left knee injury that would doom his season. It was to the same knee on which the quarterback had twice torn his ACL, though tests this time revealed no structural damage.

Bradford made a brief return in Week 5 against the Chicago Bears, but he was pulled before halftime after reaggravating the injury. He spent the better part of two months on injured reserve before being activated as Case Keenum's backup during the postseason.

The former Heisman Trophy winner and first-round pick by the St. Louis Rams in 2010 has made $114 million over his career, but injuries have haunted Bradford. He missed half of the 2013 season and all of 2014 after tearing his ACL in back-to-back years.

He's played in all 16 games just twice in his career -- in 2010, when he was an NFL All-Rookie Team selection, and again in 2012.

According to the NFL Network, Bradford has said his knee injury subsided in recent months, allowing him to return to practice ahead of the postseason, and that he "absolutely" intends to keep playing in 2018.

"I think it's been really encouraging for me, mentally, to know that I can go back out there and do it," Bradford said after returning to practice in January. "I'm just happy to be on the field."

Bradford is one of three Vikings quarterbacks set to become unrestricted free agents on Wednesday.

For his career, Bradford has started 80 games with the Vikings, Rams and Eagles. He has thrown for 19,049 yards, 101 touchdowns and has completed 62.5 percent of his passes. He also has had 57 interceptions and 33 fumbles.